Craz I fly low fuel load planes and still dont find any of that trouble. Besides 90% of everything is 10k or below in the game.
Navy planes, the Yank ones, are poor climbers in comparison to the Zero or Spit. But a Hellcat GIVES you a fast 10K on WEP alone.
Many times with extra tanks Ive taken a Spitfire or Hellcat and flew CAP over a CV for long periods by simply managing my power. Like they had to do in real life. Its a mistake we often make in gaming, having the throttle on full all the time. The best here can manage their throttles, and their energy, and make you look bad in any contest at any Alt.